Loans, Allowance for Loan Losses and Allowance for Unfunded Credit Commitments - Allowance for Loan Losses Individually and Collectively Evaluated for Impairment (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Financing Receivable, Impaired [Line Items]
Individually Evaluated for Impairment	$ 44,859	$ 37,941
Financing Receivable, Individually Evaluated for Impairment	153,009	170,074
Collectively Evaluated for Impairment	260,065	242,962
Financing Receivable, Collectively Evaluated for Impairment	33,011,627	28,168,206
Commercial loans
Financing Receivable, Impaired [Line Items]
Individually Evaluated for Impairment	44,648	37,675
Financing Receivable, Individually Evaluated for Impairment	147,529	165,835
Collectively Evaluated for Impairment	238,770	223,291
Financing Receivable, Collectively Evaluated for Impairment	29,240,421	25,138,802
Commercial loans \| Software/internet
Financing Receivable, Impaired [Line Items]
Individually Evaluated for Impairment	26,613	28,527
Financing Receivable, Individually Evaluated for Impairment	95,572	114,850
Collectively Evaluated for Impairment	73,610	75,040
Financing Receivable, Collectively Evaluated for Impairment	6,103,976	6,039,905
Commercial loans \| Hardware
Financing Receivable, Impaired [Line Items]
Individually Evaluated for Impairment	1,214	1,253
Financing Receivable, Individually Evaluated for Impairment	5,458	11,506
Collectively Evaluated for Impairment	18,430	18,472
Financing Receivable, Collectively Evaluated for Impairment	1,365,701	1,223,051
Commercial loans \| Private equity/venture capital
Financing Receivable, Impaired [Line Items]
Individually Evaluated for Impairment	0	0
Financing Receivable, Individually Evaluated for Impairment	0	3,700
Collectively Evaluated for Impairment	115,805	98,581
Financing Receivable, Collectively Evaluated for Impairment	17,801,324	14,106,860
Commercial loans \| Life science/healthcare
Financing Receivable, Impaired [Line Items]
Individually Evaluated for Impairment	16,414	7,484
Financing Receivable, Individually Evaluated for Impairment	31,612	34,067
Collectively Evaluated for Impairment	22,831	24,696
Financing Receivable, Collectively Evaluated for Impairment	2,336,436	2,351,545
Commercial loans \| Premium wine
Financing Receivable, Impaired [Line Items]
Individually Evaluated for Impairment	204	0
Financing Receivable, Individually Evaluated for Impairment	11,922	1,301
Collectively Evaluated for Impairment	4,944	3,355
Financing Receivable, Collectively Evaluated for Impairment	1,076,295	958,362
Commercial loans \| Other
Financing Receivable, Impaired [Line Items]
Individually Evaluated for Impairment	203	411
Financing Receivable, Individually Evaluated for Impairment	2,965	411
Collectively Evaluated for Impairment	3,150	3,147
Financing Receivable, Collectively Evaluated for Impairment	556,689	459,079
Consumer loans
Financing Receivable, Impaired [Line Items]
Individually Evaluated for Impairment	211	266
Financing Receivable, Individually Evaluated for Impairment	5,480	4,239
Collectively Evaluated for Impairment	21,295	19,671
Financing Receivable, Collectively Evaluated for Impairment	$ 3,771,206	$ 3,029,404

The valuation allowance for financing receivables that are expected to be uncollectible that were collectively evaluated for impairment.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=118936363&loc=SL6953423-111524

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Amount of valuation allowance for financing receivables that are expected to be uncollectible that were individually evaluated for impairment.

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The balance of financing receivables that were collectively evaluated for impairment.

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-Publisher FASB
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